Large-scale deployment of 3rd generation mobile communications greatly drives usage of a data service, and accurate charging of the data service is a basis for conduction of the data service. Policy and charging control (Policy and Charging Control, PCC) is a set of policy and charging control mechanisms defined by the 3rd Generation Partnership Project (3rd Generation Partnership Project, 3GPP). The core of a PCC mechanism is as follows: When establishing a bearer for a data stream, a gateway (GateWay) device requests a charging control policy of the data stream from a policy and charging rules function (Policy and Charging Rules Function, PCRF); if an application function (Application Function, AF) provides service-layer information of a service for the PCRF, the PCRF generates a dynamic control policy for charging and service data stream or determines a static control policy to be activated for charging and service data stream, according to subscriber information stored in a subscription profile repository (Subscription Profile Repository, SPR), bearer-layer information provided by the gateway, certain local policies that are configured by an operator in the PCRF and the service-layer information. The PCRF delivers a command for installing the generated dynamic policy or activating the determined static policy stored in the gateway to a policy and charging enforcement function (Policy and Charging Enforcement Function, PCEF) in the gateway; and the PCEF performs, according to the installed/activated policy, resource allocation, data stream control, and charging control. The PCC mechanism can implement, according to a policy of the operator, precise control on a service data stream, so as to implement fine-grained operation of bandwidth.
In the preceding PCC mechanism, the AF is a service network element, and provides information related to a service accessed by a subscriber. For example, the AF can provide information such as a service identifier, a service priority indication, and a service urgency indication for the PCRF.
In the PCC, the PCRF is a policy decision entity responsible for controlling QoS, bandwidth, gating, charging control policies, and so on when a user equipment uses a service in a home network, and generating a dynamic policy or specifying a static policy, where the policy is executed by the policy and charging enforcement function.
The PCEF is a policy execution entity, and is configured to execute a dynamic control policy delivered by the PCRF or a specified static control policy, and may be located in a gateway device, such as a GGSN, a P-GW, or a WAP gateway.
The SPR is a subscription data storage entity and stores subscription data of the subscriber.
When the PCEF performs charging control, a case where a rate group changes may appear in certain scenarios. With regard to a change of a rate group on a side of a network element, the prior art has not provided an appropriate processing method for a charging system to perform charging. As a result, after the rate group changes, an existing charging system fails to receive accurate information and then fails to perform precise processing according to the change of the rate group, thereby affecting charging accuracy. Meanwhile, because accurate processing cannot be performed on the change of the rate group, a problem where partial traffic before service identification cannot be accurately charged may appear in PCRF-based data service charging control.